In the EKOS focuser panel, what brings the focus to the INTRAFOCAL : the IN- or the OUT-button ?
Thanks and sorry for the silly question.

On my system in takes you intrafocal, but that is because I sat and watched as I pushed the in button to see which direction it went. It turned out that one of my focusers, an EAF, was backwaards, so I set it to reversed in the settings. The other, a Pegasus FocusCube, turned out to be correct. It is just the side of the focuser I put it on that made the difference.
Hope that helps a little.

Thanks for the suggestion Dave , but this made me more confused because I have a MicroTouch Autofocuser.
May be the answer is : IN = INtra-focal , and thus OUT = Extra-focal
But this remains a guess.

That is indeed how it is intended. But you have to properly adjust the reverse setting of the focuser driver. Because nothing in the system can know how your focus motor is mounted. So you need to check in which direction it moves when you move, e.g., INwards. If the focus tube then extends, you haave to toggle the reverse setting.

It's an important thing to set properly, because focus algorithms like Linear and L1P rely on this: They end their move inwards, assuming that this moves things against gravity. If that is not the case, the backlash correction might be unreliable...

Thank you for this clear answer Peter.
I check visually what are the effects of the IN- and OUT-buttons on the mirror position :
The IN-button moves the mirror towards the observer, the OUT-button moves it towards the stars (i.e. against gravity).
If I understand it well, the IN-button moves the image to INTRAFOCAL and the OUT-button moves the image to EXTRAFOCAL
Correct ?

Ah, so this is a mirror telescope that focuses by moving the main mirror. Makes things more complicated.
For a cassegrain system, if you increase the distance between primary and secondary, the focus point moves inwards. That is the same as moving the camera outwards (i.e., towards extrafocal). So it's inverted, and you should change the setting in the driver.
That also matches what you want regarding gravity movement: That focusing IN moves against the gravity.

(Hope I didn't goof up - it's still early in the morning.....)

No, I don't think so because I checked that : "the OUT-button moves the main mirror towards the stars (i.e. against gravity)"
As far I could see there is no way to change this setting in the driver

I got this message from the Starizona people. This clears up the matter.

"The IN button pulls the primary mirror back, which moves the focus "in" toward the telescope, both with HyperStar or at the back of the scope. The OUT button moves focus out (so extrafocal) by pushing the primary mirror forward. This can be reversed in the MicroTouch Controller software, but those are the defaults. Let us know if you have more questions!"

So is that 'reverse' option only in their (I assume win-only) software?
Anyhow their wording is a bit misleading: "The OUT button moves focus out (so extrafocal)"
If you're in focus, and then move the focus point OUT, your camera will be at / see the intrafocal position (assuming this is what your initial question aimed at?)